Strip type mining and space comprehensive utilization method for end slope coal pressing of strip mine

Abstract

The invention discloses a strip-type mining and space comprehensive utilization method for end slope coal pressing of a strip mine. The method comprises the three steps of water interception frozen soil column arrangement, door-shaped alternate mining and filling and underground space utilization. On one hand, the water interception frozen soil column plays a role in blocking water source supply of a far-end aquifer and keeping a mining working face dry through freezing water insulation, and on the other hand, mechanical properties of open-pit mine end slope soft rock, crack development rock and various rocks with cracks containing water are enhanced through freezing, the resistance is provided for the end slope, and the mining working face is protected. The stability of the end slope is improved; the door-shaped frame provides a local stable environment for end slope coal pressing mining; concentrated long-time disturbance to a certain position of the end slope is avoided through the alternate mining mode; the underground mining cavern formed by the even-number sections is used for storing water, under the condition that mine production safety is not affected, underground space is fully utilized, the dumping site can provide heat preservation for the water storage cavern in the end slope, water resource freezing is avoided, and the water using problem of strip mines in the north in winter is effectively solved.

Description

Technical Field

[0001] The invention relates to a strip mining method for end-wall compressed coal, and in particular to a strip mining method for end-wall compressed coal and a space comprehensive utilization method for an open-pit mine. Background Art

[0002] ‌ Mining coal from the side walls of open-pit mines is an important way to increase the mining rate of open-pit mines and improve the economic benefits of mining companies. Especially for open-pit mines with thick coal seams, the mining demand for coal from the side walls is urgent and the profits are considerable. At present, the mining of coal from the side walls of open-pit mines has become an important way to recover coal from the side walls. The main process is to recover coal from the side walls by digging horizontal or inclined tunnels at the side walls. Because of its mature mining technology, complete supporting equipment and high mining efficiency, it is favored by more and more open-pit mines and its scope of use is becoming more and more extensive. However, the geological conditions in different regions of my country vary greatly. In some areas, the rock cracks in the roof of the coal seams are very well developed and have poor mechanical properties. In some areas, the roof of the coal seams contains a large amount of groundwater, the rock is soft and the bearing capacity is limited. Using traditional mining methods, it is very easy to cause roof collapse. Therefore, it is urgent to propose a method for mining coal from the side walls of open-pit mines with water-containing soft rock roofs. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for strip mining and comprehensive space utilization of compressed coal at the end of an open-pit mine, which is suitable for mining compressed coal at the end of an open-pit mine with water-containing soft rock roof. The roof has good stability during mining and is not affected by groundwater.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for strip mining and comprehensive space utilization of open-pit mine end-wall compressed coal, including three steps of arranging water-cutting frozen soil columns, alternating mining and filling with gates, and utilizing underground space; Arrangement of water-blocking frozen soil columns: At a distance of 30-50m outside the recovery boundary of the side pressure coal of the open-pit mine, drill vertically downward along the spoil dump toward the mining area, with the drilling depth exceeding 3-5m below the lower boundary of the side pressure coal, and the interval between adjacent boreholes not less than 2m. A frozen soil pipe is installed inside the borehole, and the frozen soil pipe is connected to an external freezing device. The freezing device transmits cold energy to the frozen soil pipe, thereby freezing the rocks and water around the corresponding borehole to form a water-blocking frozen soil column; Door-type alternating mining and filling: Divide the end-wall coal to be mined into several sections in sequence along the direction from the spoil dump to the stope, leaving an intermediate coal with a width of C between two adjacent sections. The width A of the odd-numbered sections and the width B of the even-numbered sections should satisfy A=B+2C; A top frozen soil layer is constructed at the top coal-rock interface of the first section, and frozen support columns are constructed within the range C outside the left and right boundaries of the first section. The left and right ends of the top frozen soil layer extend to the outside of the frozen support columns. The top frozen soil layer and the frozen support columns on both sides form a door-shaped frame. After the door-shaped frame is constructed, a mining tunnel is arranged in the "door-shaped" and the coal therein is mined until the end wall boundary. At this time, the width of the mining tunnel is the full width A of the first section; During the mining process of the first section, the portal frame and the mining tunnel are constructed and mined in the third section in the same manner. At this time, the width of the mining tunnel is the full width A of the third section. After the mining shaft of the first section is mined to the boundary, the mining shaft of the first section is filled with paste, and at the same time, the portal frame and mining shaft are constructed and mined in the fifth section. In the same way, the mining shaft of the third section is also filled with paste after it is mined to the boundary. When the filling bodies of the first section and the third section reach the strength, the freezing work of the frozen support columns on both sides of the first section and the third section is completed, and then the top frozen soil layer is constructed at the top coal-rock interface of the second section. At this time, the top frozen soil layer and the filling bodies on both sides of the second section form a portal frame. After the portal frame of the second section is constructed, the mining shaft is arranged in the "gate" and the coal is mined until the end wall boundary. At this time, the width of the mining shaft is the full width B of the second section and the full width C of the middle coal on both sides, that is, B+2C; after the mining of the even-numbered sections is completed, the water-blocking frozen soil column behind the mining shaft stops supplying cooling, and the frozen soil pipe is taken out for recycling; And so on, according to the above method, the odd-numbered sections and even-numbered sections are continuously mined; Utilization of underground space: After the mining of the even-numbered sections is completed, the internal surface of the mining tunnel is strengthened and support devices are installed. The bottom and two sides of the mining tunnel are waterproofed and the mining tunnel mouth is sealed, thereby forming an internal water storage cave at the end wall, and then the spoil dump follows up and covers it.

[0005] Furthermore, the method for constructing the top frozen soil layer and frozen support columns is to first drill a hole, extract the coal resources, install a freezing pipe in the drill hole and freeze it, and then form the top frozen soil layer and frozen support columns after freezing.

[0006] Furthermore, two rows of holes are symmetrically arranged at intervals on the side of the freezing pipe.

[0007] Furthermore, after the freezing work of the freezing support column is completed, additional grouting is injected into the freezing pipe.

[0008] Furthermore, when the top frozen soil layer of the even-numbered section begins to be constructed, 1 / 3 of the width of the top frozen soil layer of the odd-numbered section extending to the even-numbered section is thawed first, and then the top frozen soil layer is constructed at the top coal-rock interface of the even-numbered section.

[0009] Furthermore, a hole is drilled from the surface of the spoil dump above the internal water storage cave into the internal water storage cave to form a water well and a pumping device is arranged.

[0010] Compared with the prior art, the water-blocking frozen soil column inside the present invention, on the one hand, utilizes freezing to isolate water, thereby blocking the water supply of the distant aquifer and keeping the mining face dry; on the other hand, freezing strengthens the mechanical properties of soft rock at the end wall of the open-pit mine, rock with developed cracks, and various types of rock containing water in the fissures, thereby providing resistance to the end wall and improving the stability of the end wall, thereby providing a reliable construction environment for the implementation of the present invention; the portal frame provides a local stable environment for end wall compressed coal mining; the alternating mining method avoids concentrated and long-term disturbances to a certain position of the end wall; the underground mining shafts formed in the even-numbered sections are fully utilized for water storage, and the underground space is fully utilized without affecting the safety of mine production. The overlying spoil dump can provide insulation for the water storage cave inside the end wall, avoid freezing of water resources, effectively solve the water use problem in northern open-pit mines in winter, and improve mine efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the section division and construction stages of the present invention; Figure 2 This is a schematic diagram of the arrangement of water-cutting frozen soil columns of the present invention; Figure 3 This is a top view of the construction position of the present invention; In the figure: 1. Coal pressure at the end wall; 2. Recovery boundary; 3. Ground surface; 4. Water-blocking frozen soil column; 5. Dumping area; 6. Mining area; 7. Section 1; 8. Section 2; 9. Section 3; 10. Section 4; 11. Section 5; 12. Section 6; 13. Section 7; 14. Middle coal; 15. Top coal-rock interface; 16. Top frozen soil layer; 17. Frozen support column; 18. Portal frame; 19. Mining equipment; 20. Support device; 21. Internal water storage cave; 22. Water well. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings.

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] like Figures 1 to 3As shown, the present invention provides a method for strip mining and comprehensive space utilization of open-pit mine end-wall compressed coal, including three steps of arranging water-blocking frozen soil columns, gate-type alternating mining and filling, and underground space utilization.

[0015] Arrangement of water-blocking frozen soil columns: At a distance of 30-50m outside the recovery boundary 2 of the end wall coal 1 of the open-pit mine, drill downward vertically at intervals of 3 along the spoil dump 5 toward the mining area 6. The drilling depth is 3-5m deeper than the lower boundary of the end wall coal 1. The row and line spacing of the boreholes are adjusted according to the geological and hydrological conditions. The more complex the geological and hydrological conditions are, the smaller the row and line spacing are. The interval between adjacent boreholes is not less than 2m. A frozen soil pipe is installed inside the borehole. The frozen soil pipe is a cylindrical pipe with an open end and closed sides. The frozen soil pipe is connected to an external freezing device. The freezing device transports cold air into the frozen soil pipe, thereby freezing the rocks and water around the corresponding borehole to form a water-blocking frozen soil column 4.

[0016] The functions of the water-blocking frozen soil column 4 are mainly divided into two aspects: on the one hand, it uses freezing to isolate water and block the water supply of the distant aquifer to keep the mining face dry; on the other hand, it plays the role of an anti-slip pile. Since the overall stability of the end wall is reduced due to well mining, the water-blocking frozen soil column 4 can provide resistance for the end wall to prevent the end wall from sliding.

[0017] Door-type alternating mining and filling: like Figure 1 As shown, the end wall pressure coal 1 to be mined is divided into several sections in sequence along the spoil dump 5 toward the mining area 6. In this example, the end wall pressure coal 1 to be mined is divided into section No. 1 7, section No. 2 8, section No. 3 9, section No. 4 10, section No. 5 11, section No. 6 12 and section No. 7 13. An intermediate coal 14 with a width of C is left between two adjacent sections. The width A of the odd-numbered sections and the width B of the even-numbered sections should satisfy A=B+2C. According to actual conditions, the width A of the odd-numbered sections is generally about 25m, the width B of the even-numbered sections is generally about 15m, and the width C of the intermediate coal 14 between two adjacent sections is generally about 5m. In this way, it can be ensured that the actual mining widths of the odd and even sections are equal in combination with subsequent process steps, which facilitates the consistency of selection of mining and support equipment.

[0018] A top frozen soil layer 16 is constructed within a range of 2.5m above and below the top coal-rock interface 15 of section 1, that is, within a total height of 5m. A frozen support column 17 is constructed within a range of 5m outside the left and right boundaries of section 1. The method for constructing the top frozen soil layer 16 and the frozen support column 17 is to first drill a hole with an auger, extract a small amount of coal resources, install a freezing pipe in the drill hole and freeze it, and then form the top frozen soil layer 16 and the frozen support column 17. Two rows of holes are symmetrically arranged at a certain distance on the side of the freezing pipe. The purpose of setting the holes on the side is to carry out secondary grouting later to achieve One tube serves two purposes; in order to increase the supporting strength of the top frozen soil layer 16, the left and right ends of the top frozen soil layer 16 extend to the outside of the frozen support column 17, and the extension width is generally 8m; the top frozen soil layer 16 and the frozen support columns 17 on both sides form a portal frame 18, and the portal frame 18 can provide effective support for the coal mining in its "portal". After the portal frame 18 is constructed, a mining shaft is arranged in the "portal" and the coal therein is mined until the end wall boundary. The mining process can be carried out using existing underground mining equipment 19 and processes. At this time, the width of the mining shaft is the full width of section 7 No. 1, that is, 25m.

[0019] During the mining process of section No. 1 section 7, the portal frame 18 and the mining shaft are constructed and mined in section No. 3 section 9 according to the same method. At this time, the width of the mining shaft is the full width of section No. 3 section 9, i.e. 25m. After the mining shaft of section No. 1 section 7 is mined to the boundary, the mining equipment 19 is withdrawn, and then the mining shaft of section No. 1 section 7 is filled with paste. At the same time, the portal frame 18 and the mining shaft are constructed and mined in section No. 5 section 11. According to the same method, the mining shaft of section No. 3 section 9 is also filled with paste after it is mined to the boundary.

[0020] When the filling bodies of Section 1 7 and Section 3 9 reach the required strength, the freezing work of the frozen support columns 17 on both sides of Section 1 7 and Section 3 9 is terminated, and then the frozen pipes are supplemented with grouting, and the frozen pipes with holes are used for supplementary grouting to make up for the frozen pipe space and the collapsed volume caused by the partial melting of the frozen paste to ensure that the strength is sufficient; after the supplementary grouting is completed, the top frozen soil layer 16 is constructed at the top coal-rock interface 15 of Section 2 8, and the top frozen soil layer 16 of Section 2 8 is constructed. When the construction of 16 begins, the top frozen soil layer 16 of the No. 1 section 7 and the No. 3 section 9 extending to the No. 2 section 8 is first thawed by 1 / 3 of the width, and then the top frozen soil layer 16 is constructed within the range of 2.5m above and below the top coal-rock interface 15 of the No. 2 section 8, that is, the total height of 5m. The top frozen soil layer 16 of the No. 2 section 8 and the top frozen soil layers 16 of the No. 1 section 7 and the No. 3 section 9 on both sides are frozen into a whole, thereby improving the support effect; at this time, the top frozen soil layer 16 and The filling bodies of Section 1 7 and Section 3 9 on both sides of Section 2 8 form a portal frame 18. After the portal frame 18 of Section 2 8 is constructed, a mining tunnel is arranged in the "gate" and the coal therein is mined until the end wall boundary. At this time, the width of the mining tunnel is the sum of the full width of Section 2 8 and the full width of the middle coal 14 on both sides thereof, that is, 15+2*5=25m. In this way, the final mining width of the even-numbered sections and the odd-numbered sections is kept the same, and there is no need to purchase or adjust additional coal mining equipment, which reduces mining costs and improves mining efficiency. Efficiency; after the mining of section No. 2 8 is completed, the cooling of the water-blocking frozen soil column 4 at the rear of the mining tunnel, that is, near the side of the spoil dump 5, is stopped, and the frozen soil pipe is taken out for recycling. Because the section has been mined and filled at this time, there is no fear of water seepage, and the cooling should be stopped in time to reduce energy consumption; by analogy, according to the above method, the odd-numbered sections and even-numbered sections are continuously mined, that is, in the process of mining odd-numbered sections, whenever there is an even-numbered section that meets the condition of "the odd-numbered sections on both sides have been completed with replenishment and filling", this even-numbered section is mined.

[0021] There is a sequential relationship in the implementation of the two steps of arranging water-cutting frozen soil columns and portal-type alternating backfilling mining. The former provides the necessary safe hydrological and geological guarantees for the implementation of the latter. Therefore, the two processes are not simply spliced ​​together, but support each other.

[0022] Utilization of underground space: After the mining of the even-numbered sections is completed, the interior of the mining tunnel is no longer filled, but the interior surface of the mining tunnel is strengthened and a support device 20 is installed. The bottom surface and two sides of the mining tunnel are waterproofed and the mining tunnel mouth is blocked, thereby forming an internal water storage cave 21 of the end wall, and then the dump 5 quickly follows up and covers. After the internal water-blocking frozen soil column 4 and the door-shaped frozen soil are released, the water inside the end wall flows and gathers to the internal water storage cave 21 of the end wall. At the same time, the groundwater at the far end will also gather into the internal water storage cave 21 of the end wall, thereby storing a large amount of water resources underground. A water well 22 is formed from the surface of the dump 5 above the internal water storage cave 21 to the internal water storage cave 21, and a pumping device is arranged to utilize the water resources stored in the underground space. The overlying dump 5 can provide insulation for the internal water storage cave 21 to prevent water resources from freezing, effectively solving the winter water problem of open-pit mines in the north.

[0023] Since the construction stages of each section are different at the same time, in order to show the status of each section at different stages more clearly and completely, Figure 1 Section No. 1 7, Section No. 3 9 and Section No. 5 11 are in the stage of being mined and filled, Section No. 2 8 is in the stage of internal water storage cave 21 and water well 22 have been built, Section No. 4 10 and Section No. 7 13 are in the stage of being mined, and Section No. 6 12 is in the stage of waiting to be mined.

[0024] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any slight modification, equivalent substitution and improvement made to the above embodiment based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A method for strip mining and comprehensive space utilization of open-pit mine end-wall coal, characterized in that: It includes three steps: arranging water-blocking frozen soil columns, alternating mining and filling in gate-type, and utilizing underground space; Arrangement of water-blocking frozen soil columns: At a distance of 30-50m from the outer side of the recovery boundary (2) of the open-pit mine side pressure coal (1), drill holes vertically (3) downward along the spoil dump (5) in the direction of the mining area (6), the drilling depth is 3-5m beyond the lower boundary of the side pressure coal (1), and the interval between adjacent boreholes is not less than 2m. A frozen soil pipe is installed inside the borehole, and the frozen soil pipe is connected to an external freezing device. The freezing device transmits cold energy to the frozen soil pipe, thereby freezing the rocks and water around the corresponding borehole to form a water-blocking frozen soil column (4); Gate type alternating mining and filling: The end-wall pressure coal (1) to be mined is sequentially divided into a plurality of sections along the direction from the spoil dump (5) to the stope (6), with an intermediate coal (14) of width C being left between two adjacent sections, and the width A of the odd-numbered sections and the width B of the even-numbered sections satisfying A=B+2C; A top frozen soil layer (16) is constructed at the top coal-rock interface (15) of the first section, and frozen support columns (17) are constructed within the range C outside the left and right boundaries of the first section. The left and right ends of the top frozen soil layer (16) extend to the outside of the frozen support columns (17). The top frozen soil layer (16) and the frozen support columns (17) on both sides form a door-shaped frame (18). After the door-shaped frame (18) is constructed, a mining tunnel is arranged in the "door shape" and the coal therein is mined until the end wall boundary. At this time, the width of the mining tunnel is the full width A of the first section. During the mining process of the mining tunnel in the first section, the door-shaped frame (18) and the mining tunnel are constructed in the third section according to the same method and the mining tunnel is mined. At this time, the width of the mining tunnel is the full width A of the third section. After the first section of the mining tunnel is mined to the boundary, the first section of the mining tunnel is filled with paste, and at the same time, the door frame (18) and the mining tunnel are constructed in the fifth section and the mining tunnel is mined. In the same way, the third section of the mining tunnel is also filled with paste after the mining reaches the boundary. When the filling body of the first section and the third section reaches the strength, the freezing work of the freezing support columns (17) on both sides of the first section and the third section is completed, and then the top frozen soil layer (15) is constructed at the position of the top coal-rock interface (15) of the second section. 16), at this time, the top frozen soil layer (16) and the filling bodies on both sides of the second section form a door-shaped frame (18). After the door-shaped frame (18) of the second section is constructed, a mining tunnel is arranged in the "door-shaped" and the coal therein is mined until the end wall boundary. At this time, the width of the mining tunnel is the full width B of the second section and the full width C of the middle coal (14) on both sides thereof, that is, B+2C. After the mining of the even-numbered sections is completed, the water-blocking frozen soil column (4) at the rear of the mining tunnel stops supplying cooling, and the frozen soil pipe is taken out for recycling; And so on, according to the above method, the odd-numbered sections and even-numbered sections are continuously mined; Utilization of underground space: After the mining of the even-numbered sections is completed, the internal surface of the mining tunnel is reinforced and a support device (20) is installed. The bottom surface and two side surfaces of the mining tunnel are waterproofed and the mining tunnel mouth is sealed, thereby forming an internal water storage cave (21) at the end wall, and then the spoil dump (5) follows up and covers.

2. The method for strip mining and comprehensive space utilization of open-pit mine end-wall coal according to claim 1, characterized in that: The method for constructing the top frozen soil layer (16) and the frozen support column (17) is to first drill a hole, extract the coal resources, install a freezing pipe in the drill hole and freeze it, and then form the top frozen soil layer (16) and the frozen support column (17) after freezing.

3. The method for strip mining and comprehensive space utilization of open-pit mine end-wall coal according to claim 2, characterized in that: Two rows of holes are symmetrically arranged at intervals on the side of the freezing pipe.

4. The method for strip mining and comprehensive space utilization of open-pit mine end-wall coal according to claim 3 is characterized by: After the freezing work of the freezing support column (17) is completed, additional grouting is injected into the freezing pipe.

5. The method for strip mining and comprehensive space utilization of open-pit mine end-wall coal according to claim 3 is characterized by: When the top frozen soil layer (16) of the even-numbered section begins to be constructed, the top frozen soil layer (16) of the odd-numbered section extending to the even-numbered section is first thawed by 1 / 3 of its width, and then the top frozen soil layer (16) is constructed at the top coal-rock interface (15) of the even-numbered section.

6. The method for strip mining and comprehensive space utilization of open-pit mine end-wall coal according to claim 1, characterized in that: A hole is drilled from the surface of the spoil dump (5) above the internal water storage hole (21) into the internal water storage hole (21) to form a water intake well (22) and a water pumping device is arranged.

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